Dust dissemination poses safety, health and environmental problems in many commercial environments. For example, dust suppression is of particular concern in the coal mining industry where coal dust dissemination caused by wind or transit motion may lead to black lung disease if inhaled over lengthy periods of time. Ignition of small dust particles is also a concern. Similar concerns exist when other materials such as sulfur, phosphates, clays or other finely divided ores and minerals generate dust in handling operations, during mining, transportation, storage or use.
In addition to the mining industry, many other commercial activities also provide the potential for dust control problems. For instance, fertilizer dust has raised health concerns due to human and animal inhalation and also poses the problems of ignition or explosion. The cement industry also is concerned with fugitive dust dissemination during manufacture, transport and storage operations.
Industrial sources of fugitive dust include open operations, leaks and spills, storage, disposal, transit and/or poor housekeeping where sundry finely divided solid particulates are involved. In noncommercial settings, dust generation may pose health and safety problems, as with the fertilizer use, as well as housekeeping or aesthetic problems.
In combination with the concerns and problems involved with the manufacture, storage and handling of items inclined to the formation of fugitive dust, concerns related to biological organisms also exist with respect to these items. For example, the production of acidic leachate i.e., acid mine drainage, found in coal and coal refuse piles is related to biological activity in the piles. Surfactant based biocides have been known to reduce the population of bacteria responsible and thereby inhibit acid mine drainage. Dried sewage sludge which can be used as fertilizer or mixed with coal for use as a fuel exhibits both dust generation problems and odor caused by biological action. Similarly, grain and animal feed which exhibit well known problems with respect to dust generation could be beneficially treated with biological agents to control insect or rodent damage or spoilage.
Thus, in numerous areas where dry, bulk or granular solids are manufactured, stored and handled the combination of dust generation and biological activity are of concern. Thomas, U.S. Pat. No. 4,847,067 discloses the treatment of grain or hay to control the moisture induced growth of mold. The treatment also provides dust control. The described treatment comprises an aqueous solution of one or more salts of propionic acid and a deliquescent material and preferably also a humectant. The aqueous treatment is sprayed onto the grain or hay.
The use of foams as dust control agents is known in the coal mining industry. For example, Cole U.S. Pat. No. 4,400,220 discloses the use of foam of a specific small bubble size to control dust in coal mining operations at the working face and at transfer points. Roe, U.S. Pat. No. 4,780,233 discloses a water insoluble elastomeric polymer and oil combination which may be applied in a foam carrier to inhibit dust dissemination. Ellis, U.S. Pat. No. 865,578 discloses a non-foam dust control agent for application to a road surface.
Other, agricultural uses for foams are known such as for freeze control. For example, Cole, U.S. Pat. No. 3,563,461 discloses a system of applying foam to agricultural plants to inhibit freeze damage. Lambou et al., U.S. Pat. No. 3,891,571 discloses a foam containing whey solids for use as frost and freeze protection for plants. The foam of Lambou et al. can be used as a carrier for the surface application of agricultural chemicals such as herbicides, fungicides, etc.